package com.lu.练习0_leetcode.链表;

import com.lu.练习3_链表.List;

/**
 * https://leetcode-cn.com/problems/linked-list-cycle/
 * @author xiaolu
 * @version 1.0
 * @date 2020/10/29 12:39
 */
public class _141_环形链表 {
    // 快慢指针
    public boolean hasCycle(ListNode head) {
        if (head == null || head.next == null) return false;

        ListNode slow = head;
        ListNode fast = head.next;

        while (fast != null && fast.next != null) {

            slow = slow.next;
            fast = fast.next.next;

            if (slow == fast) return true;
        }
        return false;
    }
}
